IEC 60079-14 Best Practices: What to Check Before an Ex Installation Is Accepted

Installing electrical equipment in a hazardous area is not simply a matter of mounting certified Ex equipment and connecting the cables. The equipment, installation method, cable entries, protection concept, documentation, and actual hazardous area conditions all need to be considered together.

IEC 60079-14 provides requirements for the design, selection, installation, and initial inspection of electrical installations in explosive atmospheres. In practice, however, many installation problems occur because individual components are checked separately rather than as part of the complete installation.

This guide focuses on practical checks that can help engineers, contractors, inspectors, and procurement teams review an Ex installation before it is accepted.

1. Confirm the Hazardous Area Before Selecting Equipment

The first question should not be which Ex equipment to buy. It should be whether the equipment is suitable for the hazardous area where it will be installed.

Confirm the applicable hazardous area classification and identify the type of explosive atmosphere involved, such as gas, vapour, mist, or combustible dust.

The equipment selection should then be checked against the applicable area classification and required protection level.

Best practice: Keep the hazardous area classification drawing or documentation available during equipment selection and installation review. Equipment should not be selected based only on voltage, power rating, enclosure size, or product availability.

2. Verify the Ex Equipment Before Installation

Certified Ex equipment can still be unsuitable for a particular installation. The certification marking needs to be reviewed against the actual application.

Check items such as:

• Equipment protection concept
• Equipment group
• Gas or dust group, where applicable
• Temperature class or maximum surface temperature
• EPL or applicable equipment category
• Ambient temperature range
• Certificate number
• Special conditions of use, where applicable

Best practice: Do not treat the presence of an Ex marking as sufficient evidence that the equipment is suitable. The complete marking should be compared with the hazardous area requirements.

3. Check the Certificate and Product Marking Together

The information on the equipment should be consistent with the applicable certificate and product documentation.

This is particularly important when equipment is supplied through distributors or when several product variants have similar model numbers.

A practical verification should compare:

• Model or type designation
• Ex marking
• Certificate number
• Manufacturer information
• Relevant electrical ratings
• Special conditions stated in the certificate

Best practice: Verify the certificate before installation rather than discovering a certification mismatch during inspection or commissioning.

4. Do Not Select Cable Glands Based on Cable Size Alone

Cable gland selection is one of the areas where a nominal cable size does not provide enough information.

The actual cable construction and dimensions may affect gland selection. Depending on the application, the installer may need to consider the cable outer diameter, bedding diameter, armour arrangement, inner sheath, and other physical characteristics.

For Ex installations, the gland must also be suitable for the equipment and the applicable protection concept.

Best practice: Check the actual cable construction and measured dimensions against the manufacturer's gland selection range before installation.

5. Check the Cable Entry as Part of the Ex Protection System

An Ex enclosure can only maintain its intended protection when the cable entry system is installed correctly.

The review should include the compatibility between:

• Ex equipment enclosure
• Cable gland
• Cable construction
• Sealing arrangement
• Thread type and size
• Earthing or bonding requirements, where applicable

Best practice: Treat the cable gland as part of the Ex installation, not simply as an accessory used to connect the cable to the enclosure.

6. Check Special Conditions of Use

Some certified Ex equipment has special conditions that must be observed during installation or operation. These conditions may be identified in the certificate using specific marking conventions.

Examples may include requirements relating to:

• Mechanical protection
• Ambient temperature
• Electrostatic considerations
• Specific cable or gland arrangements
• Installation orientation
• Other conditions identified by the certification

Best practice: Review the complete certificate and installation instructions whenever special conditions are identified. Do not assume that the standard product installation method applies to every certified variant.

7. Confirm the Installation Matches the Equipment Protection Concept

Different types of explosion protection have different installation considerations. An installation method that is acceptable for one protection concept may not be appropriate for another.

For example, requirements associated with an Ex d enclosure can differ significantly from those associated with increased safety or other protection concepts.

The installation should therefore be reviewed according to the actual protection concept indicated on the equipment.

Best practice: Identify the protection concept from the equipment marking first, then verify the installation details against the applicable requirements and manufacturer's documentation.

8. Check Mechanical Installation Details

Ex equipment should not be considered acceptable simply because it is electrically connected and operational.

Mechanical installation details can also affect the integrity of the protection provided by the equipment.

Check items such as:

• Enclosure condition
• Unused entries and their closures
• Fasteners and covers
• Gland installation
• Mechanical support
• Protection against physical damage
• Correct installation orientation where specified

Best practice: Include mechanical condition and installation details in the Ex inspection rather than focusing only on electrical connections.

9. Do Not Assume Installation Is Complete When the Equipment Is Mounted

Mounting the equipment is only one stage of the installation.

Before acceptance, the complete installation should be reviewed against the design information, equipment documentation, installation requirements, and applicable hazardous area classification.

This can include checking:

• Equipment identification
• Cable entries
• Connections
• Earthing and bonding
• Enclosure integrity
• Equipment location
• Documentation

Best practice: Perform an installation review before energization or final acceptance instead of relying on visual confirmation that the equipment has been physically installed.

10. Keep Installation Documentation Traceable

Documentation is an important part of an Ex installation because the suitability of the installed equipment may need to be verified later during inspection, maintenance, or modification.

Useful records can include:

• Equipment datasheets
• Ex certificates
• Equipment schedules
• Hazardous area classification documents
• Cable and gland information
• Installation records
• Inspection records

Best practice: Maintain a clear connection between the installed equipment, its identification, and its supporting certification and documentation.

Common Mistakes During Ex Installation

Several recurring mistakes can be avoided with a structured installation review.

• Selecting equipment based only on electrical ratings
• Checking the Ex marking but not the certificate
• Selecting cable glands from cable conductor size alone
• Ignoring special conditions of use
• Using the same installation approach for different Ex protection concepts
• Leaving documentation verification until commissioning
• Assuming a certified component automatically makes the complete installation compliant

Practical Ex Installation Acceptance Checklist

The following checklist can be used as a practical starting point during an installation review:

Check	What to Verify
Hazardous Area	Area classification matches the intended equipment application
Ex Equipment	Protection concept and Ex marking are suitable
Certificate	Certificate information matches the equipment
Temperature	Temperature class or maximum surface temperature is suitable
Ambient Conditions	Equipment operating range is suitable for the installation
Cable Gland	Gland is suitable for the cable and Ex application
Cable Entry	Entry and sealing arrangement are correctly installed
Special Conditions	Certificate conditions have been addressed
Mechanical Installation	Enclosure, covers, fasteners, and entries are correctly installed
Documentation	Equipment and installation records are traceable

What IEC 60079-14 Requirements Mean in Practice

IEC 60079-14 should not be treated only as a document to consult when an Ex installation problem occurs. Its requirements provide a framework for making sure that equipment selection and installation are appropriate for the intended hazardous area.

The practical objective is to connect several pieces of information that are often handled separately: the hazardous area classification, equipment certification, Ex marking, cable and gland selection, installation method, and supporting documentation.

That connection is where many installation errors can be identified before they become commissioning or inspection problems.

Important Note

This article provides practical guidance based on IEC 60079-14. It does not reproduce or replace the requirements of the standard.

The checks in this article should be verified against the applicable edition of IEC 60079-14, project specifications, equipment certification, and applicable local regulations.

Sources

• IEC 60079-14 — Explosive atmospheres — Part 14: Electrical installation design, selection and erection
• IEC 60079-0 — Explosive atmospheres — Part 0: Equipment — General requirements
• IECEx — International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres

Conclusion

A successful Ex installation is more than installing equipment that carries an explosion protection marking. The equipment must be suitable for the hazardous area, correctly certified, properly installed, and supported by the appropriate cable entry system and documentation.

A structured review before acceptance can identify many issues before they become commissioning delays, inspection findings, or costly modifications.